Electronic mail (e-mail) is an essential network service. Most e-mail systems that send mail over the Internet use simple mail transfer protocol (SMTP) to send messages from one server to another. The messages can then be retrieved with an e-mail client using services such as post office protocol (POP) or Internet message access protocol (IMAP). Other protocols for sending e-mail include POP3, X.400 International Telecommunication Union standard (X.400), and the Novell message handling service (MHS), and extended simple mail transfer protocol (ESMTP). Specifically, X.400 defines a transfer protocol for sending electronic mail between mail servers and is used in Europe as an alternative to SMTP. MHS, which was developed by Novell, is used for electronic mail on Netware networks.
SMTP transports electronic mail among different hosts within the transmission control protocol/Internet protocol (TCP/IP) suite. Under SMTP, a client SMTP process opens a TCP connection to a server SMTP process on a remote host and attempts to send mail across the connection. The server SMTP listens for a TCP connection on a specific port (25), and the client SMTP process initiates a connection on that port. When the TCP connection is successful, the two processes execute a simple request-response dialogue, defined by the SMTP protocol (see RFC 821 STD 10, Simple mail transfer protocol, August 1982, for details), in which the client process transmits the mail addresses of the originator and the recipient(s) for a message. When the server process accepts these mail addresses, the client process transmits the e-mail instant message. The e-mail message contains a message header and message text (“body”) formatted in accordance with RFC 822 (RFC822 STD 11, Standard for the format of ARPA—Internet Text Messages, August 1982). Mail that arrives via SMTP is forwarded to a remote server or it is delivered to mailboxes on the local server. On UNIX-based systems, Sendmail is the most widely used SMTP server for e-mail. Sendmail includes a POP3 server and also comes in a version for Windows NT. Microsoft Outlook is the most popular mail-agent program on Window-based systems.
The SMTP model (RFC 821) supports both end -to-end (no intermediate message transfer agents “MTAs”) and store-and-forward mail delivery methods. The end-to-end method is used between organizations, and the store-and-forward method is chosen for operating within organizations that have TCP/IP and SMTP-based networks. A SMTP client will contact the destination host's SMTP server directly to deliver the mail. It will keep the mail item from being transmitted until it has been successfully copied to the recipient's SMTP. This is different from the store-and-forward principle that is common in many other electronic mailing systems, where the mail item may pass through a number of intermediate hosts in the same network on its way to the destination and where successful transmission from the sender only indicates that the mail item has reached the first intermediate hop. The RFC 821 standard defines a client-server protocol. The client SMTP is the one which initiates the session (that is, the sending SMTP) and the server is the one that responds (the receiving SMTP) to the session request. Because the client SMTP frequently acts as a server for a user-mailing program, however, it is often simpler to refer to the client as the sender-SMTP and to the server as the receiver-SMTP. An SMTP-based process can transfer electronic mail to another process on the same network or to another network via a relay or gateway process accessible to both networks. An e-mail message may pass through a number of intermediate relay or gateway hosts on its path from a sender to a recipient.
A simple model of the components of the SMTP system is shown in FIG. 1. Users deal with a user agent (UA). Popular user agents for UNIX include Berkeley Mail, Elm, MH, Pine, and Mutt. The user agents for Windows include Microsoft Outlook/Outlook Express and Netscape/Mozilla Communicator. The exchange of e-mail using TCP is performed by an MTA. The most common MTA for UNIX systems is Sendmail, and a conventional MTA for Windows is Microsoft Exchange 2000/2003. Users normally do not deal with the MTA. It is the responsibility of the system administrator to set up the local MTA. Users often have a choice, however, for their user agent. The local MTA maintains a mail queue so that it can schedule repeat delivery attempts in case a remote server is unable. Also the local MTA delivers mail to mailboxes, and the information can be downloaded by the UA (see FIG. 1). The RFC 821 standard specifies the SMTP protocol, which is a mechanism of communication between two MTAs across a single TCP connection. The RFC 822 standard specifies the format of the electronic mail message that is transmitted using the SMTP protocol (RFC 821) between the two MTAs. As a result of a user mail request, the sender-SMTP establishes a two-way connection with a receiver-SMTP. The receiver-SMTP can be either the ultimate destination or an intermediate one (known as a mail gateway). The sender-SMTP will generate commands, which are replied to by the receiver-SMTP (see FIG. 1).
Both the SMTP client and server have two basic components: UA and local MTA. There are few cases of sending electronic-mail messages across networks. In the first case of communication between the sender and the receiver across the network (see FIG. 1), the sender's UA prepares the message, creates the envelope, and puts message in the envelope. The MTA transfers the mail across the network to the TCP-port 25 of the receiver's MTA. In the second case of communication between the sending host (client) and the receiving host (server), relaying could be involved (see FIG. 2). In addition to one MTA at the sender site and one at the receiving site, other MTAs, acting as client or server, can relay the electronic mail across the network. This third scenario of communication between the sender and the receiver can be accomplished through the use of an e-mail gateway, which is a relay MTA that can receive electronic mail prepared by a protocol other than SMTP and transform it to the SMTP format before sending it. The e-mail gateway can also receive electronic mail in the SMTP format, change it to another format, and then send it to the MTA of the client that does not use the TCP/IP protocol suite. In various implementations, there is the capability to exchange mail between the TCP/IP SMTP mailing system and the locally used mailing systems. These applications are called mail gateways or mail bridges. Sending mail through a mail gateway may alter the end-to-end delivery specification, because SMTP will only guarantee delivery to the mail-gateway host, not to the real destination host, which is located beyond the TCP/IP network. When a mail gateway is used, the SMTP end-to-end transmission is host-to-gateway, gateway-to-host or gateway-to-gateway; the behavior beyond the gateway is not defined by SMTP.
E-mail across SMTP, or the other protocols references above, is used extensively today to communicate relevant personalized information. For example, a company needs to frequently communicate to each of its numerous consumers with relevant personalized e-mail. In such a situation, companies often maintain information specific to each of its customers or clients in a data repository, such as customer databases, data files, customer relationship management (CRM) systems, and the like. One approach for communicating with all of these customers is to send personalized individual, batch, or bulk e-mail through an e-mail distributor or high-throughput mail transfer agent (MTA) system.
A mail transfer agent or MTA (also called a mail server, or a mail exchange server in the context of the Domain Name System) is a computer program or software agent that transfers electronic mail messages from one computer to another. Webster's New World Computer Dictionary, tenth edition, Wiley Publishing Inc., Indianapolis, Ind., defines an MTA as an e-mail program that sends e-mail messages to another message transfer agent. An MTA can handle large amounts of mail, can interact with databases in many formats, and has extensive knowledge of the many SMTP variants in use. Examples of high-throughput MTA systems are disclosed in U.S. patent application Ser. No. 10/857,601, entitled “Email Delivery System Using Metadata,” filed May 27, 2004 as well as U.S. patent application Ser. No. 10/777,336, entitled “Email Using Queues in Non-persistent memory,” filed Feb. 11, 2004, each of which is hereby incorporated by reference in its entirety. One example of an MTA system is the StrongMail MTA (Redwood Shores, Calif.). Conventional MTA programs include, but are not limited to, sendmail, qmail, Exim, and Postfix.
High-throughput MTA systems such as those described above are more powerful than conventional MTA programs. Both high-throughput and conventional MTA products can send out messages to a plurality of recipients. However, while functional, existing MTA systems are unsatisfactory. To illustrate why, consider the case in which company A wishes to communicate with existing or past customers. The company maintains a record of each of these customers in a company database. Such records may contain personalized information about each of the customers. Company A wishes to use this information in order to customize each of the e-mails. To accomplish this, a method for accessing the customer information in the database needs to be arranged. Separately, the design of the e-mail that will be sent to each customer in the distribution list needs to be created. Therefore, at a minimum, what is needed is coordination between an information technology (IT) specialist and a business development professional in order to configure data from one or more sources to create messages to be delivered using the MTA distribution.
An IT specialist is consulted in order to provide a secure method for querying the database containing customer information. For instance, the IT specialist might set up an account with limited database privileges as well as construct scripts with customized database queries in order to obtain the information for each customer. At a minimum, such information will include an e-mail address for each customer. In more powerful examples, the names of the customers are identified, as well as other information such as the types of products the customer has bought in the past, geographic information, information about the customer payment history, how often the customer buys products, how much product the customer buys, and so forth. Thus, it is clear that an IT specialist is needed in conventional MTA based distribution efforts each time a business development professional designs a new e-mail for distribution using an MTA. The role of the business development professional is to optimize the persuasiveness and effectiveness of the customized MTA distribution. The work of the business development professional involves choosing fonts, color schemes and art that will be used in the customized e-mail sent to a plurality of recipients. The work of the business development professional further involves making decisions about which customers will receive a customized e-mail. The business development professional can, for example, select customers as a function of geographic region, amount of product bought from the company during a predetermined time period, etc. Thus, close coordination between the business development professional and the IT specialist is needed for each business development project that involves the distribution of customized electronic messages using an MTA.
The business development example provided above is just one example of the many applications that can be implemented using e-mail. Other applications include providing secure custom statements (e.g., banking statements), person-to-person customized e-mail, traceable e-mails, e-mails from customer service to existing customers, e-mails from an employer to an employee, etc. However, conventional user agents do not provide satisfactory methods for supporting such features. As the example above shows, complex steps are necessary in order to support such applications. Accordingly, given the above background, what are needed in the art are improved systems and methods for generating and interpreting customized e-mail messages for distribution.
Discussion or citation of a reference herein will not be construed as an admission that such reference is prior art to the present invention.